Bag and Article of Manufacture

ABSTRACT

An article of manufacture including a bag made of a multi-layer laminate. The bag can have a front surface, a rear surface, two side surfaces, a bottom surface, and a top surface; the bag having a height, a width, and a depth, and an internal volume. The bag can be sealable and have a seal strength of at least about 1,600 pounds per square inch. The multi-layer laminate can have a thickness of from about 130 to about 200 microns. The plastic laminate can include an inner layer and an outer layer, wherein the outer layer can include a nylon and the inner layer can include a polyethylene. The plastic laminate can have a dart drop resistant of at least about 5 grams/mil and a tear resistance of at least about 6 grams/mil and 9 grams/mil in the machine direction and cross direction, respectively.

FIELD

The invention relates generally to bags for containing particulate, flowable compositions. More particularly, embodiments of the present invention relate to bags that can be made of laminates.

BACKGROUND

Industries that use and sell large quantities of bulk, particulate, flowable compositions, such as animal food, bulk foods, coffee, fertilizer, detergent, and the like are often faced with the task of packaging and shipping such compositions in containers suitable for shipping, handling, retail sale, and consumer transport and use. For compositions such as bulk animal foods, such containers are typically paper or plastic bags containing up to about 75 pounds of food composition. Such containers therefore must be able to withstand shipping and handling without breaking open.

Bags for containing and handling bulk compositions are made from various materials and secured closed in various ways depending on the properties of the bag materials, the properties of the closure systems, and cost considerations. Materials used for such bags include burlap, paper, multi-layer, and plastics. Closure for one-time use can be accomplished by stitching, taping, gluing, heat sealing, and/or ultra sonic welding the containers closed after the containers are filled with the composition. The cost to produce such bags and closures varies with the type of bag material and type of closure used. In the retail pet food industry, such bags have typically been made from multiple layers of paper, plastic, and/or foil, and stitched, taped, glued, heat sealed, and/or ultrasonically welded closed.

The materials and closures of such bags are typically selected to provide the most cost-effective container, considering material cost, material properties, closure cost, closure properties, damage and lost product due to bag breakage, etc. Bags for containing quantities of 15 or more pounds of dry pet food composition are typically multiple layered paper bags, often lined with plastic or foil on an interior surface thereof, that are stitched, taped and/or glued closed.

However, paper bags do not keep the food compositions contained therein particularly fresh over time. Oxygen, moisture, and even perhaps organisms can enter the bags. Thus, in time, the food may oxidize, become stale, become infested, and generally become less palatable to the animal and less desirable by the animal owner. Additionally, bags that are stitched, taped and/or glued closed can not be resealed once opened. Therefore, many animal owners resort to emptying the contents of the paper bag into a storage container that can be easily accessed, easily reclosed, and that keeps the food fresh.

Furthermore, such feed bags are typically rectangularly shaped with very small depth versus height of such bags. Thus, the bags must be stacked and displayed laying flat on one of the largest surfaces, typically the front or back surface. Such orientation, particularly for bags containing 15 or more pounds of composition, makes the bags difficult to display and to remove and lift. If such bags are successfully removed from a store shelf, they are often deposited on a narrow bottom surface of the bag, and often fall over. The instability of the bags can be bothersome if one must keep righting the bag. In addition, if the bag has been taken home and opened, extensive spillage can result when the bag tips over.

Recently, manufacturers have attempted to provide bags that are reclosable and that provide enhanced spoilage protection for the contents over time, such that a user does not have to empty a large, heavy bag into a separate container. Therefore, manufacturers have begun to supply plastic bags, or paper bags with plastic or foil linings, and having reclosable features. Plastic, and plastic or foil lined materials are better moisture and air/oxygen barriers than, for example, paper or burlap, and provide better protection from spoilage and infestation.

However, it has been found that many such plastic bags burst open, when filled with about 15 or more pounds of bulk composition, and dropped off of a truck, a store shelf, out of a user's vehicle or grip, or when tipped over. The bursting problem is often exacerbated when such bags are formed with a reclosable feature. Such bags can burst at the site of the reclosable feature or at one or more seals or seams of the bag, or the material forming the bag itself can tear and cause the bag to burst open. In addition, plastic bags can be slippery to the touch, and can result in a greater amount of bags dropped versus other materials such as paper or burlap.

Some manufactures have attempted to solve the problem of bags bursting at a reclosable feature by placing and sealing a material over or across the reclosable feature, which the consumer then removes once the bag is safely at its final destination. Such an approach is feasible with various paper bags, and quantities of composition over about 15 pounds in weight. However, many plastic bags still burst when they contain over about 15 pounds of material and fall from a height of about 3 feet, whether or not the bags contain a reclosable feature. Thus, the majority of bags used for containing greater than about 15 pounds of dry pet food are various types of paper bags. Other approaches include sealing the inside of the bag in addition to having a reclosable feature. Using a double thickness in the reclosable feature is another option. However, cost can increase prohibitively as more components are added to the bag.

Therefore, there is a need for a plastic bag that can contain amounts of compositions and can withstand a drop from heights without bursting open. There is also a need for such a bag to be reclosable. There is a need for such a bag to also provide moisture and oxidation barrier protection for the contents. There is also a need for the bag to be stable when situated upright on a bottom surface of the bag, and for the bag to be easily grippable.

SUMMARY

Embodiments of the present invention relate to articles of manufacture comprising a bag. The bag can be used for containing large quantities of particulate, flowable compositions such as dry pet food. The bags can comprise a multi-layer laminate having a thickness of from about 130 to about 200 microns; wherein the plastic laminate comprises a polyamide. The plastic laminate can have a dart drop resistant of at least about 5 grams/mil and a tear resistance of at least about 6 grams/mil and 9 grams/mil in the machine direction and cross direction, respectively. The bag having a height between about 18 inches and 40 inches, a width between 11 inches and 18 inches, and a depth between 2.5 inches and 9 inches and can contain at least about 10 liters of a particulate, flowable composition contained in the bag.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a bag of one embodiment of the present invention.

FIG. 2 is a perspective view of an alternative embodiment of the present invention.

FIG. 3 is a perspective cutaway view showing a bag of one embodiment of the present invention filled with particulate, flowable composition.

FIG. 4 is a top perspective view of a bag illustrating a non-reusable closure of one embodiment of the present invention.

FIG. 5 is a cross-sectional side view of the membrane of one embodiment of the invention.

FIG. 6 is a perspective view of a bag having a non-reusable closure partially installed therein.

FIGS. 7 a-c are perspective views of the non-reusable closure of one embodiment of the present invention illustrating the targeted openable region.

DETAILED DESCRIPTION

All measurements made herein art made at 25° C. unless otherwise designated.

The term “particulate, flowable compositions”, as used herein and usable with the present invention, means compositions including animal feeds including rodent, dog, cat, horse, goat, cattle, pig, bird, and the like; detergents; fertilizers; cat litter; bulk foods including grains, nuts, beans, fruits, and the like.

The term “slack fill”, as used herein, means to fill a container with a composition during manufacturing and/or packaging such that the composition occupies a volume less than the interior volume of the container, thereby leaving a “head space”, meaning empty portion of volume, in the container.

The term “seal”, as used herein, means the seal or seals that form the bag itself, and which can be formed by sealing the surfaces, such as the inner surfaces, of the plastic laminate together; and in addition means the seals formed when sealing a non-reusable closure to the top of the bag, if such a non-reusable closure is used.

The term “seal strength”, as used herein, refers to a measure of tensile strength at each seal made and used in forming the bag.

Article of Manufacture Bag

One embodiment of the present invention encompasses articles of manufacture illustrated in FIGS. 1-7. As shown in FIGS. 1 and 2, the article of manufacture comprises a bag 10 comprising a front surface 12 and a rear surface 14 extending upwardly from a bottom surface 16, which can be flattenable, especially when formable material is used to construct the article. Two side surfaces 18 each can be an expandable gusset 20, which can include a region of the side surface that folds to form a crease, therein connecting front surface 12 and rear surface 14 at opposite sides of bag 10. The bag 10 also can have a flattenable bottom surface 16 that can be formed by connecting front surface 12, rear surface 14, and side surfaces 18. Bag 10 also can have a top surface 22 formable by connecting front surface 12, rear surface 14, side surfaces 18, and located opposite flattenable bottom surface 16. The bag has a height H, a width W, a depth D. The height H, width W, and depth D of bag 10 are defined and measured as internal dimensions of bag 10, measured from the inside surfaces of the bag. The height H is measured along the front or rear face of the bag from the inside edge of the bottom seal to the top edge of the bag, not including any closure. The width is measured across the front or rear face of the bag from inside of edge seal to inside of edge seal at a midpoint of the height of the bag. The depth is measured across either side surface from edge seal to edge seal at a midpoint of the height of the bag. The height H, width W, and depth D define an internal volume V.

The bag 10 can be sealable by methods commonly known in the art, such as, for example, heat sealing, along at least one edge of a side surface 18 a, 18 b, bottom surface 16, and top surface 22. The bag can also be sealed at each edge 18 a, 18 b. Such a bag, sealed at each of the four side edges, can be commonly referred to as a “quad seal” bag. A quad seal bag is one embodiment described herein. The seals of the bag can have a seal strength of at least about 1,600 pounds per square inch. The bag can comprise a plastic laminate having a thickness of from about 130 to about 200 microns. The plastic laminate can have an impact dart-drop resistance of at least about 6.2 grams/mil, and a tear resistance of at least about 7.9 grams/mil and 10.8 grams/mil in the machine direction and cross direction respectively.

The article of manufacture can comprise, in addition to the bag, at least about 15 pounds of a particulate, flowable composition contained therein. Alternatively, the article of manufacture can comprise at least about 20 pounds of the particulate, flowable composition, alternatively at least about 30 pounds of the particulate, flowable composition, and alternatively at least about 40 pounds of the particulate, flowable composition. The article of manufacture can comprise up to about 75 pounds of particulate, flowable composition. From a volume perspective, the article, alternatively or additionally with respect to the weight above, can contain at least about 10 liters of a particulate, flowable compositions, or at least about 15 liters, or at least about 20 liters, or at least about 30 liters, or at least about 40 liters, or at least about 75 liters.

The bag 10 of the article of manufacture of the present invention can be formed to have any particular dimensions and any particular shape. An embodiment of bag 10 of the present invention, as shown in FIGS. 1 and 2, can have a ratio of width W to height H of from about 0.4 to about 0.8. Alternatively, the ratio of width W to height H can be about 0.6. Such a ratio of width W to height H can help to ensure that bag 10 is stable and resistant to tipping such that bag 10 can be easily placed and stored on its bottom surface 16. Such a ratio can result in more of the composition contained inside the container to be situated such that the potential for tipping can be decreased. Furthermore, such a width W to height H ratio can help distribute forces generated on the plastic laminate and seals if the bag is dropped, such that the width W to height H ratio aids in making the bag resistant to breaking or bursting if dropped. Such a ratio can allow forces to distribute by providing more surface area for the forces to contact and dissipate through.

Bag 10 also can have a ratio of depth D to height H of from about 0.17 to about 0.4. Alternatively bag 10 can have a depth D to height H ratio of from about 0.17 to about 0.3. The depth D can be represented by side surface 18. The depth D to height H ratio can also aid in ensuring that bag 10 can be easily placed and stored on its bottom surface 16 and be resistant to tipping. In addition, the depth D to height H ratio can also help distribute forces generated on the plastic laminate and seals if bag 10 is dropped, such that the depth D to height H ratio aids in making bag 10 resistant to breaking or bursting if dropped. Such a ratio allows forces to distribute by providing more surface area for the forces to contact and dissipate through.

Such ratios are not commonly found in commercially available bags. Most commercially available side gusseted bags have rather small side gussets, and thus, very small depth to height ratios. Such small depth to height ratios result in bags that have small bottom surfaces, and which effectively can not be stood on the bottom surface without tipping over. Therefore, conventional pet feed bags must be displayed laid down on either the front or rear surface and cannot effectively be used throughout the period of use of the composition contained therein because they do not stand up well. In addition plastic laminate bags with small side gussets are much less burst-resistant due to the small surface area of the sides having the gussets. When such bags are dropped, particularly on the small, gusseted sides, they are likely to burst due to the forces created due to the small surface area of the gusseted sides.

Therefore, an example combination of ratio of width W to height H, and ratio of depth D to height H, of a bag of one embodiment of the present invention, is about 0.6 and about 0.20. A bag 10 of one embodiment of the present invention, when formed as described, can withstand a drop from at least about 4 feet, on one of gusseted sides 18, when filled with at least about 15 pounds of particulate, flowable composition, and can be very stable and resistant to tipping. Thus, such a bag can be displayed and sold in an upright, vertical position and can be easily used as the storage container for the composition contained therein, throughout the use of the composition.

Bags of embodiments of the present invention can have varying absolute dimensions for height, width, and depth. The height can range from about 18 inches to about 40 inches, or from about 20 inches to about 40 inches, or from about 20 inches to about 39 inches, and all numeric ranges therebetween. The width can range from about 11 inches to about 18 inches, or from about 13 inches to about 18 inches, or from about 13 inches to about 17.75 inches, and all numeric ranges therebetween. The depth can range from about 2.5 inches to about 9 inches, or from about 3 inches to about 9 inches, or from about 3 inches to about 8.5 inches, and all numeric ranges therebetween. Any combination of these dimensions can be used.

As shown in FIG. 3, bag 10 of one embodiment of the present invention also defines an internal volume V, which can be at least about 20% greater than a volume Vc occupied by the composition contained within bag 10, thus creating a head space volume Vh. The bags can be slack filled such that the composition does not occupy the entire internal volume V of the bag. The head space volume Vh allows bag 10 to be easily and securely sealed after filling, helps to distribute forces generated if bag 10 is dropped to help ensure bag 10 is burst resistant, and, in combination with the depth D and gussets 20, provides a grippable portion 24, as seen in FIGS. 1 and 2 near the top surface 22 by which bag 10 can be grasped for lifting.

An embodiment of bag 10 can comprise a non-reusable closure 26, shown in FIG. 4, that can aid in ensuring bag 10 is burst resistant and can provide a tamper evident indicator. Non-reusable closure 26 can have a length that extends along said width W of bag 10. Non-reusable closure 26 can comprise a membrane 28 disposed, such as by connected or otherwise attached, between front surface 12 and rear surface 14 of bag 10. The membrane 28 can have a thickness of from about 170 to about 200 microns. In one embodiment, non-reusable closure 26 can be utilized on bag 10 in the machine direction of the material of membrane 28.

Membrane 28 can have a user-facing surface 30, an outer surface 32 (as shown in FIG. 5), and a tear strength of at least about 15 pounds per square inch (PSI), as measured in the transverse or cross machine direction, by ASTM Method D-882 Standard Test Method for Tensile Properties of Thin Plastic Sheeting. Non-reusable closure 26 can be disposed at a top edge 34 of bag 10 or, alternatively, can be disposed inward a distance from top edge 34 of bag 10. In FIG. 4, non-reusable closure 26 is shown located at top edge 34 of bag 10.

As shown in FIG. 5, membrane 28 can have a plurality of ribs 36 on outer surface 32 of membrane 28, which enable outer surface 32 to be sealed to front surface 12 of bag 10, and a plurality of ribs 36 on outer surface 32 of membrane 28 which enable outer surface 32 to be sealable to rear surface 14 of bag 10 to seal bag 10 closed.

FIG. 6 illustrates a membrane 28 employed on a bag 10. A plurality of ribs 36 (as shown in FIG. 5) on outer surface 32 of membrane 28 can be sealable to an inner surface 12 a of front surface 12 and to a top portion 20 a of an inner surface 20 b of gussets 20. A plurality of ribs 36 on outer surface 32 of membrane 28 can be sealable to an inner surface 14 a of rear surface 14 and to a top portion 20 a of an inner surface 20 b of gussets 20. When membrane 28 is sealed to bag 10, the seal can seal to the top portion 20 a of gussets 20 as well as front and back surfaces 12 and 14. Such a seal can be accomplished by methods commonly known in the art, such as, for example, heat sealing.

When the article of manufacture is being manufactured, bag 10 can be formed, the top portion thereof open. Ribs 36 a of outer surface 32 of membrane 28 can then be sealed to inner surface 12 a of front surface 12 and top portions 20 a of gussets 20. The bag 10 can be filled, and then ribs 36 b of outer surface 32 can be sealed to inner surface 14 a of rear surface 14 and top portions 20 a of gussets 20 to seal bag 10 closed and form top surface 22.

Such a closure allows for top filling of bags. However, such a closure could also be completely sealed at the top of the bag, and form the top surface 22, before filling and be used with a bottom fill process without having the closure break or burst during the bottom fill process.

Although membrane 28 provides excellent burst resistance, a tear strength of greater than about 15 pounds per square inch proves difficult for a user to open by hand. Because it can be desired that the article of manufacture of the present invention also be easy for an ultimate consumer or user to open by hand, membrane 28 comprises a targeted opening region 38. Targeted opening region 38 can have a tear strength, measured in the transverse or cross machine direction by ASTM Method D-882, of from about 1 to about 15 pounds per square inch, alternatively of from about 3 to about 12 pounds per inch, alternatively from about 4 to about 10 pounds per inch, alternatively from about 4 to about 9 pounds per inch, and alternatively from about 5 to about 7 pounds per inch.

During development of the bags of some embodiments of the present invention, it was found that known non-reusable closures and tamper evident features have opening regions that extend the entire length of the membrane, i.e. essentially the entire width of the bag. Such opening regions typically consist of one or more score lines, perforations, or other material-weakening features. However, it was found that such opening regions, while being easily opened by a consumer, by hand, also can become a region of weakness and bursting when bags filled with for example, 15 or more pounds of dry pet food, are dropped, sometimes from as low as 18 inches. Such drops are common in the shipping and handling of large, heavy bags containing various particulate, flowable compositions and cause damage and loss of product, and annoyance to retailers and consumers.

Therefore, the burst-resistant bag 10 of one embodiment of the present invention comprises targeted opening region 38 that comprises from about 1% to about 90% of a length L of membrane 28. Alternatively targeted opening region 38 comprises from about 1% to about 50% of the length L of membrane 28, alternatively from about 1% to about 30% of the length L of membrane 28, and alternatively of from about 1% to about 10% of the length L of membrane 28. Furthermore, it was found that when the opening region extends to, or is located within, about 5% of either end 28 a, 28 b of the length L of membrane 28, even if the opening region only comprises a small percentage, for example about 10-20%, of the length L of membrane 38, burst resistance is decreased. Thus, even small opening regions, when located at the end(s) 28 a, 28 b, of membrane 28, decrease burst resistance. Therefore, the “targeted opening region” 38 of one embodiment of the present invention means, and has the proviso that, the opening region does not extend to within about 5% of either end 28 a, 28 b of membrane 28. Targeted opening region 38 can be located anywhere along the length L of membrane 28, within the definition of the targeted opening region, or can be centered at a midpoint M along the length L of membrane 28 and width W of bag 10. Targeted opening region 38 can be located at or near a midpoint m of the width w of membrane 28 and can be disposed inboard a distance from top edge 34 of bag 10. FIGS. 7 a-c illustrate various locations and sizes of one embodiment of targeted opening region 38.

As can be seen in FIGS. 7 a-c, targeted opening region 38 can comprise a plurality of perforations 40 in membrane 28. Targeted opening region 38 can also comprise and be formed by laser scoring, heat scoring, or mechanical weakening of any type such as removing a portion of material.

Also shown in FIGS. 7 a-c, membrane 28 can also comprise instructional indicia 42 on user-facing surface 30 of membrane 28. Such instructional indicia 42 can comprise printing including words, pictures, symbols, illustrations, and the like, to indicate to the user where and how to open the non-reusable closure 26.

Membrane 28 can be formed from a material selected from the group consisting of ethylene derived polymer, polypropylene, polyester, polyolefins, homopolymer and/or co-polymer polyolefins, and combinations thereof. Particularly, membrane 28 can comprise an ethylene-derived polymer selected from the group consisting of low density polyethylene, high density polyethylene, ultra-low density polyethylene, and combinations thereof. The particular combination of material can be selected based on balancing strength of the material for burst resistance with openability for ease of use of the bag 10. The material can be devised and formed based on its ability to seal securely to the plastic laminate of bag 10 to provide the required seal strength of at least about 1,600 pounds per square inch. The material of the membrane can be a co-extruded blend of low density polyethylene, high density polyethylene, and ultra low/very low density polyethylene, with ultra low/very low density polyethylene forming ribs 36 and 36 such that the ribs seal to the inner surfaces of the bag at a temperature that can be less than about 68° C. The number of ribs 36 can depend on the width w of the membrane. The spacing of the ribs 36 on membrane 28 can depend on the type and strength of seal desired.

In addition to finding a particular material for the membrane 28 that provides burst resistance and allows for openability, the dimensions of membrane 28 can be important with respect to burst resistance, seal strength, ease of sealing during manufacturing, and openability. Membrane 28 can have a width w of from about 1.5 inches to about 3 inches. Alternatively, membrane 28 can have a width of from about 2 inches to about 3 inches. Alternatively, membrane 28 can have a width of about 3 inches. When the total width w of the membrane 28 is about 3 inches, there can be about ten to fifteen (10-15), alternatively about fourteen (14) ribs 36 on outer surface 32, as illustrated previously in FIG. 5.

Production and creation of the particular plastic laminate can be advantageous such that when the laminate is used for bags that contain particulate, flowable compositions are often dropped during shipping and handling. Conventional, commercially available such bags often burst when dropped from a height of as low as 18 inches, when filled with as little as 15 pounds of composition. Such bursting causes damage and lost product as well as messes and annoyance to retailers and consumers. In particular, bags that have reclosable features tend to burst at the site of the reclosable feature. Thus, currently available resealable feed bags are generally not available in capacities greater than about 15 pounds, and/or have the reclosable feature taped over, or otherwise additionally reinforced.

When bags containing large amounts, such as the amounts disclosed herein, such as up to 75 pounds or up to 75 liters, of particulate, flowable compositions burst, several elements of the bag can fail. If the bag has a reclosable feature, the forces generated by a drop of the bag can cause the composition contained therein to burst through the reclosable feature. The seals that form the bag can separate and fail. The material from which the bag itself is made, for example, the plastic laminate, can tear or burst open. The material from which the laminate is made, as well as the thickness of the laminate affect its burst resistance.

Therefore, in some embodiments of the present invention it can be advantageous to create an appropriate laminate having a balance of strength and stretchability (measured by tensile strength), flexibility and stiffness (measured by secant modulus), texture, thickness, and cost-effectiveness. Particular laminates may have a high tensile strength, and therefore a high resistance to stretching, which can be useful. However, in some instances, such a laminate may be brittle or stiff (i.e. have a high secant modulus), and because it resists stretching, may burst easily and therefore may not be useful or particularly preferred in some bags of the present invention. In addition, a laminate usable with embodiments of the present invention can also have a suitable texture and not be extremely slippery. Bags containing at least about 15 pounds of a particulate, flowable composition can be difficult to pick up and carry because of the weight of material contained therein, especially when the materials used for construction of the bag are slippery or difficult to grip. Thus, bags containing such materials should ideally not be slippery or difficult to grip.

In addition, the laminate can be securely sealable to form the bag by methods known the art such as heat sealing. The laminate can be cost-effective as well, and plastic laminate bags are more costly than traditional paper feed bags. Thus, in one embodiment, as thin a layer of laminate as possible can be used from a cost-effective standpoint. However, the thickness of the laminate in combination with its composition affects its likelihood to burst if dropped. Thus, material composition and thickness can also be considered.

Bag 10 of embodiments of the present invention can have a seal strength of at least about 1,600 pounds per square inch as measured by ASTM Method D-882. Alternatively, bag 10 can have a seal strength of at least about 1,800 pounds per square inch.

The plastic laminate forming the bag can have an impact dart-drop resistance of at least about 5 grams/mil as measured by ASTM Method D-1709-04, and a tear resistance of at least about 6 grams/mil and 9 grams/mil as measured in both the machine direction (MD) and transverse or cross machine direction (CD), respectively, by ASTM Method D-1922. Alternatively, the plastic laminate can have an impact dart drop resistance of at least about 5.5 grams/mil and a tear resistance of at least about 7 grams/mil (MD) and about 10 grams/mil (CD). Alternatively, the plastic laminate can have an impact dart drop resistant of at least about 6.2 grams/mil and a tear resistance of at least about 7.9 grams/mil (MD) and 10.8 grams/mil (CD).

The plastic laminate of the bag can have a secant modulus of from about 30,000 to about 110,000 pounds per square inch, as measured in both the machine and transverse or cross machine directions by ASTM Method D-882.

Bag 10 can be formed from a plastic laminate selected from the group consisting of ethylene-derived polymer, polypropylene, polyester, teraphthalates, polyolefins, homopolymer and or co-polymer polyolefins, woven polypropylene, ployamides, and combinations thereof. More particularly, the plastic laminate can be selected from the group consisting of ethylene-derived polymers such as polyethylenes in combination with a polyamide, such as Nylon 6,6. In order to be sealable to itself and to the material of a non-reusable closure, if one is employed, the material of the inner surface of the laminate can have a relatively low melting point such that it melts to enable heat sealing, whereas the outer surface can have a higher melting point such that it does not melt during heat sealing. Thus, an outer layer can be Nylon 6,6, and an inner layer can be a co-extruded blend of linear low density polyethylene, medium density polyethylene, and linear low density polyethylene. As used herein the densities of polyethylene, “low”, “medium”, “high”, “ultra low/very low”, have meanings as used and understood in the art for such materials.

In another embodiment, the laminate can be a multi-layer laminate. The multi-layer laminate can include many layers, such as an inner layer and an outer layer, and even more layers. In one embodiment, the multi-layer laminate can comprise a 75 gauge cast F101 Nylon outer layer and a 6.1 mil PE coex (polyethylene) inner layer. The plastic laminate can have a thickness of from about 130 to about 200 microns. Alternatively, the plastic laminate can have a thickness of from about 140 to about 170 microns.

In some embodiments, such a laminate can provide other beneficial properties. This multi-layer laminate can assist in reducing damage to the bag but can still provide a relatively high gloss, high print quality, reclosable, resealable bag than can stand up, as disclosed herein.

In addition to aiding in enabling bag 10 to be burst-resistant in one embodiment, the plastic laminate can provide oxygen and moisture barrier properties. It has been shown that plastic can be a better oxygen and moisture barrier than traditional paper for pet foods. It has also been shown that fats, carbohydrates, proteins, and other components commonly found in pet foods oxidize over time when exposed to air. Furthermore, it has been shown in some palatability tests that animals prefer, over time, food stored in plastic bags versus that stored in paper bags but not always. Thus, the articles of manufacture of embodiments of the present invention can in some embodiments also provide enhanced palatability of the oxidizable compositions contained therein.

Therefore, in one embodiment a plastic laminate can have an oxygen transmission rate of less than about 6.5 cc/100 in²/24 hours, as measured by ASTM Method D-3985, and alternatively of less than about 6.2 cc/100 in²/24 hours. A plastic laminate can also have a moisture vapor transmission rate of less than about 0.1 grams/100 in²/24 hours, when measured by ASTM Method F-1249, and alternatively of less than about 0.8 grams/100 in²/24 hours.

In another embodiment of the present invention, as shown in FIGS. 1 and 2, bag 10 can further include a reusable closure 44. As described above, the dimensions and proportions of bag 10 can be such that they provide burst resistance and enhanced stability. Thus, bag 10 can be stable when placed on bottom surface 16. The plastic laminate also can provide oxygen and moisture barrier properties to enable the composition to be stored in bag 10 over time. Therefore, providing a reusable closure enables the end user consumer to simply use bag 10 itself as the storage device for the composition.

Non-limiting examples of reusable closures of the present invention include a track and a slider system, a plastic zipper, a metal zipper, a hook and loop fastening system, a threaded closure device, a pressable sealing device, a snap sealing device, resealable adhesive, magnetic sealing device, electrostatic sealing device, and combinations thereof.

Reusable closure 44 can be disposed at top edge 34 of bag 10, as shown in FIGS. 1 and 2. Alternatively, reusable closure 44 can be disposable a distance inward from top edge 34 of said bag.

In another embodiment of the present invention, bag 10 can comprise both a non-reusable closure and a reusable closure. As described above, bag 10 can be not only burst-resistant but stable as well, such that it can be used as a reusable storage container. As described above, the proportions and dimensions of bag 10 can provide stability. Therefore, bag 10 can have a tip angle of from about 10° to about 50°, alternatively a tip angle of from about 20° to about 30°. Tip angle is measured using ASTM Method 6179.

Bag 10 can also be provided with features to equalize air pressure within the bag, to assist in providing burst resistance, and to provide an appealing visual appearance to the bag. However, such features for equalizing air pressure can also prevent oxygen transmission into the bag and infestation, i.e. prevent undesirable organisms form entering the bag. One such feature can be a valve, such as a one-way valve. Other such features are generally known to those of ordinary skill in the art.

Air pressure equalization described the escape of and entrance of air into and out bag 10. It can be important to allow air to escape from bag 10 during shipping and handling of the bags. When bags are stacked on pallets for shipping, the weight of the bags on top of each other can cause the bags to burst if there is no way for air to escape from the bags. However, once air is squeezed out of the bags, the bags can have an unappealing, ‘vacuum packed’, lumpy appearance. Thus, it can be desirable to allow air back into the bags once the bags are unloaded for display and sale.

Air pressure equalization can be accomplished by providing a plurality of perforations 46 in at least one side of bag 10, for example in each side gusset 20 as shown in FIGS. 1 and 2. Perforations 46 can be less than about 150 micrometers in diameter, alternatively less than about 100 micrometers in diameter, and alternatively less than about 70 micrometers in diameter, in order to allow air to pass there through but prevent infestation.

In addition, one or more gaps (not shown) can be provided at a seal of the bag for additional passage of air. The gap(s) can be formed by interrupting the heat sealing process, and such seals are known in the art as “skip gap” seals. To form such a “skip gap seal,” a non-continuous seal bar can be used, i.e. a seal bar having one or more gaps thereon wherein the gapped part of the seal bar would not touch the material being sealed, thus leaving an unsealed portion or “gap.” Such a “skip gap seal” can be formed on the seal formed at the bottom of the bag, at the seal formed when attaching a first portion of the membrane to the front surface of the bag, or when attaching the second portion of the membrane to the rear surface of the bag. A “skip gap seal” can be formed, for example in the final seal sealing the bag closed once it has been filled. Each gap can be of from about 70 μm to about 10 mm in length. If no non-reusable closure is used, gap(s) can be formed in any of the seals used to form the bag, as required for appropriate desired air equalization.

The gap(s) can be straight sided and can have a cylindrical or tubular shape or can be shaped and/or curved and of a length that would still allow air to pass there through, but which would provide a barrier to infestation (i.e. provide a longer, more complicated path for potentially infesting organisms). Any shaped gap can be incorporated or formed into the seal bar of the heat sealing apparatus, as would be understood by those skilled in the art.

Method of Enhancing Palatability

Embodiments of the present invention also can include methods of enhancing palatability of an oxidizable particulate, flowable composition after storage comprising the steps of:

-   -   a. providing a plastic laminate bag comprising:         -   i.) two side surfaces each having a gusset therein and             connecting the front and rear surfaces;         -   ii.) a closure system comprising a reusable closure and a             non-reusable closure, wherein said non-reusable closure             comprises a membrane having a targeted opening region, the             targeted opening region having a tear strength of from about             4 to about 10 pounds per square inch;     -   wherein the plastic laminate has a predetermined oxygen         transmission rate and a predetermined water vapor transmission         rate;     -   b. filling the plastic laminate bag with at least about 15         pounds of an oxidizable, particulate, flowable composition;     -   c. sealing the plastic laminate bag closed; thereby preventing         oxidation and spoilage and enhancing the palatability of the         composition contained therein.

The plastic laminate usable with the method can have an oxygen transmission rate of less than about 6.5 cc/100 in²/24 hours, alternatively less than about 6.2 cc/100 in²/24 hours. The oxygen transmission rate is measured, as described above, by ASTM Method D-3985. The plastic laminate can have a moisture vapor transmission rate of less than about 0.1 grams/100 in²/24 hours, alternatively less than about 0.8 grams/100 in²/24 hours. The moisture vapor transmission rate is measured, as described above, by ASTM Method F-1249.

EXAMPLES

ASTM Method 5276-98 (Reapproved 2004) “Standard Test Method for Drop Test for Loaded Containers by Free Fall” contains provisions for dropping variously shaped containers to assess various parameters such as finding an average drop height to failure, or for attaining pass/fail data. Bags of the present invention are subjected to these tests from heights of up to 6 feet, as a specification for shipping and handling requirements.

See in particular sections A1.1, A1.3. When testing bags of embodiments of the present invention, the test is a pass/fail test because required drop heights are specified. Based on experience packaging, shipping, and handling such bags, a specification is set that such bags containing at least about 20 pounds of particulate, flowable material, must pass a free fall drop from at least about 6 feet. When the bags contain at least about 40 pounds of particulate, flowable material, they must pass a free fall drop from at least about 4 feet. Failure occurs if any of the seals of the bag, any closures (whether reusable or non-reusable), or the bag material tears, splits, separates, punctures, deforms, bulges, and/or leaks.

The apparatus used for such a drop conforms to section 5 of ASTM Method 5276-98. Specifically the apparatus used is a L.A.B. Model 160A Drop Tester. The bags can be dropped on each of the six surfaces of the bag, and in particular must pass the drop test from the given drop height on at least one of the side surfaces. Single drops are performed, as in section A2.2.1, and drops on all six surfaces are performed, as in section A2.2.8. In particular, drops are performed on one or both of the two side surfaces, as in section A2.2.10, because the two side surfaces are those determined most likely to fail. The impact surface is concrete, as specified in section 5.1.5.1, and complies with sections 5.1.5.3-5. When the bags are dropped on each surface, they are dropped such that the drop complies with sections 8.4.1-8.5.

Example 1

A bag of one embodiment of the present invention can be constructed as follows.

A plastic laminate film, comprising a 12 micron thick layer of polyethylene teraphthalate (“PET”) bonded by adhesive lamination to a 140 micron thick co-extruded layer of metallocene linear low density polyethylene, medium density polyethylene, and metallocene linear low density polyethylene, (available for example from Exopack, Spartanburg, S.C., USA) is used for forming the bag. Once the bag is formed, the co-extruded polyethylene layer forms the inner surface and the PET layer forms the outer surface of the bag.

The sides of the bag are gusseted. The two edges of each side gusset on each side of the bag are sealed to form two edge seals on each side, resulting in four edge (4) seals, thus forming a “quad seal” bag. The bag is sealed at the bottom by conventional heat sealing, capturing the bottom of the side gussets therein and forming a bottom surface. The side gussets are also sealed at the bottom of f the bag with a “K-seal” as is known in the art, to allow the bottom surface to be flattenable. The side gussets are also sealed at the top of the bag with a “K-Seal”, as is known in the art, to restrict the flow of air through the connection of the gusset to the front and back panels.

A non-reusable closure membrane formed from a blend of low density polyethylene and ultra low density polyethylene is attached, by co-extrusion therewith, to a track of a slider and track zipper, for example a Slide-Rite® zipper from Pactive Corp., Lake Forest, Ill., USA. A track of a slider track zipper device is formed high density polyethylene. The track and the membrane are co-extruded. The membrane has a width w of about 3 inches as measured from inner edge to inner edge of the track. The membrane has a targeted opening region of 1.5 inches in length, disposed along the length of the membrane, and formed form a plurality of perforations. The targeted opening region is formed centered at a midpoint m of the width w of the membrane, and centered at a midpoint M of the length L of the membrane. See FIG. 7C. The targeted opening region has a tear strength (as measured by ASTM Method D-882) of between about 5-7 pounds per square inch.

The non-reusable closure membrane attached to the reusable track and slider closure is attached by heat sealing one side of the outer surface of the membrane to an inner surface of the front surface of the bag. The inner and outer surfaces of one half of each side gusset are captured by the seal. The bag is filled with 20 pounds of dry pet food. With the dimensions described herein, 20% headspace is provided and results in 5.5 inches of bag height remaining above the height of the product, which enables proper sealing of the bag. The second side of the outer surface of the membrane of the non-reusable closure is then heat sealed to the inner surface of the rear surface of the bag to close the bag. The inner and outer surfaces of the other half of each side gusset are captured by the final seal.

The bag has a height of 25 inches, a width of 13.25 inches, and a depth of 6.5 inches. Height dimensions have a tolerance of about 0.12 inches. Width dimensions have a tolerance of about 0.25 inches. Depth dimensions have a tolerance of 0.6 inches. The ratio of width to height is 0.6. The ratio of depth to height is 0.25.

A bag as described in this example will pass a drop test conducted according to ASTM Method D-5276-98 (Reapproved 2004) Standard Test Method for Drop Test of Loaded Containers by Free Fall, when dropped on any and all six surface, particularly the two side surfaces, from a height of 6 feet when filled with 20 pounds of dry dog food.

Example 2

An alternative embodiment of a bag of an article of manufacture of the present invention can be made as follows.

A plastic laminate film, comprising a 19 micron thick layer of Nylon 6,6 bonded by adhesive lamination to a 155 micron thick co-extruded layer of metallocene linear low density polyethylene, medium density polyethylene, and metallocene linear low density polyethylene, (available for example from Exopack, Spartanburg, S.C., USA), is used for forming the bag. Once the bag is formed, the co-extruded polyethylene layer forms the inner surface and the nylon layer forms the outer surface of the bag.

The sides of the bag are gusseted. The two edges of each side gusset on each side of the bag are sealed to form two edge seals on each side, resulting in four edge (4) seals, thus forming a “quad seal” bag. The bag is sealed at the bottom by conventional heat sealing, capturing the bottom of the side gussets therein and forming a bottom surface. The side gussets are also sealed at the bottom of the bag with a “K-seal” as is known in the art, to allow the bottom surface to be flattenable. The side gussets are also sealed at the top of the bag with a “K-Seal” as is known in the art, to restrict the flow of air through the connection of the gusset to the front and back panels.

A non-reusable closure membrane formed from a blend of low density polyethylene and ultra low density polyethylene is attached, by co-extrusion therewith, to a track of a slider and track zipper, for example a Slide-Rite® zipper from Pactive Corp., Lake Forest, Ill., USA. A track of a slider track zipper device is formed high density polyethylene. The track and the membrane are co-extruded. The membrane has a width w of about 3 inches as measured from inner edge to inner edge of the track. The membrane has a targeted opening region of 1.5 inches in length, disposed along the length of the membrane, and formed form a plurality of perforations. The targeted opening region is formed centered at a midpoint m of the width w of the membrane, and centered at a midpoint M of the length L of the membrane. See FIG. 7C. The targeted opening region has a tear strength (as measured by ASTM Method D-882) of between about 5-7 pounds per square inch.

The non-reusable closure membrane attached to the reusable track and slider closure is attached by heat sealing one side of the outer surface of the membrane to an inner surface of the front surface of the bag. The inner and outer surfaces of one half of each side gusset are captured by the seal. The bag is filled with 40 pounds of dry pet food. With the dimensions described herein, 20% headspace is provided and results in 5.5 inches of bag height remaining above the height of the product, which enables proper sealing of the bag. The second side of the outer surface of the membrane of the non-reusable closure is then heat sealed to the inner surface of the rear surface of the bag to close the bag. The inner and outer surfaces of the other half of each side gusset are captured by the final seal.

The bag has a height of 29 inches, a width of 17.5 inches, and a depth of 7.25 inches. Height dimensions have a tolerance of about 0.12 inches. Width dimensions have a tolerance of about 0.25 inches. Depth dimensions have a tolerance of 0.6 inches. The ratio of width to height is 0.6. The ratio of depth to height is 0.25.

A bag as described in this example will pass a drop test conducted according to ASTM Method D-5276-98 (Reapproved 2004) Standard Test Method for Drop Test of Loaded Containers by Free Fall, when dropped on any and all six surfaces, particularly the two side surfaces, from a height of 4 feet when filled with 40 pounds of dry dog food.

The dimensions and values disclosed herein are not to be understood as being strictly limited to the exact numerical values recited. Instead, unless otherwise specified, each such dimension is intended to mean both the recited value and a functionally equivalent range surrounding that value. For example, a dimension disclosed as “40 mm” is intended to mean “about 40 mm.”

All documents cited in the Detailed Description of the Invention are, in relevant part, incorporated herein by reference; the citation of any document is not to be construed as an admission that it is prior art with respect to the present invention. To the extent that any meaning or definition of a term in this document conflicts with any meaning or definition of the same term in a document incorporated by reference, the meaning or definition assigned to that term in this document shall govern.

While particular embodiments of the present invention have been illustrated and described, it would be obvious to those skilled in the art that various other changes and modifications can be made without departing from the spirit and scope of the invention. It is therefore intended to cover in the appended claims all such changes and modifications that are within the scope of this invention. 

1. An article of manufacture comprising: a) a bag comprising a front surface, a rear surface, two side surfaces, a bottom surface, and a top surface; the bag having a height, a width, and a depth, and an internal volume; wherein the bag is sealable and has a seal strength of at least about 1,600 pounds per square inch; and wherein the bag comprises a multi-layer laminate having a thickness of from about 130 to about 200 microns; wherein the plastic laminate comprises a polyamide; wherein the plastic laminate has a dart drop resistant of at least about 5 grams/mil and a tear resistance of at least about 6 grams/mil and 9 grams/mil in the machine direction and cross direction, respectively; b) the bag having a height between about 18 inches and 40 inches, a width between 11 inches and 18 inches, and a depth between 2.5 inches and 9 inches; c) at least about 10 liters of a particulate, flowable composition contained in the bag.
 2. The article of manufacture of claim 1 and wherein the bag has a tear strength of at least about 15 pounds per square inch as measured in the transverse direction.
 3. The article of manufacture of claim 1 and wherein the multi-laminate comprises an outer layer and an inner layer.
 4. The article of manufacture of claim 2 and wherein the outer layer comprises a nylon and the inner layer comprises a polyethylene.
 5. The article of manufacture of claim 4 and wherein the nylon comprises Nylon 6,6.
 6. The article of manufacture of claim 1 wherein the bag contains at least about 20 liters of said particulate, flowable composition.
 7. The article of manufacture of claim 1 wherein the bag has a ratio of said width to said height of from about 0.4 to about 0.8.
 8. The article of manufacture of claim 7 wherein the ratio of the width to the height is about 0.6.
 9. The article of manufacture of claim 1 wherein the bag has a ratio of the depth to the height of from about 0.17 to about 0.4.
 10. The article of manufacture of claim 9 wherein the bag has a ratio of the depth to the height of from about 0.17 to about 0.3.
 11. The article of manufacture of claim 1 wherein the bag has a ratio of the width to a height of from about 0.4 to about 0.8 and a ratio of the depth to the height of from about 0.17 to about 0.4.
 12. The article of manufacture of claim 1 wherein said internal volume, said depth of said bag, and said gussets, in combination form a grippable portion near said top of said bag, by which said bag can be grasped for lifting.
 13. The article of manufacture of claim 1 further comprising a non-reusable closure; wherein said non-reusable closure has a length that extends along said width of said bag, and wherein said non-reusable closure comprises a membrane between said front surface and said rear surface of said bag, said membrane having a user-facing surface, an outer surface, and a tear strength of at least about 15 pounds per square inch.
 14. The article of manufacture of claim 13 wherein said membrane comprises a targeted opening region that has a tear strength of from about 1 to about 15 pounds per square inch.
 15. The article of manufacture of claim 12 wherein said targeted opening region comprises a plurality of perforations in said membrane.
 16. The article of manufacture of claim 1 wherein said plastic laminate has an oxygen transmission rate of less than about 6.5 cc/100 in2/24 hours.
 17. The article of manufacture of claim 1 wherein said plastic laminate has a moisture vapor transmission rate of less than about 0.1 grams/100 in2/24 hours.
 18. The article of manufacture of claim 1 wherein said bag has a tip angle of from about 10° to about 50°.
 19. The article of manufacture of claim 1 wherein said composition comprises a dry pet food.
 20. The article of commerce of claim 1 and wherein the bag has a height of from about 18 inches to about 40 inches a width from about 11 inches to about 18 inches and a depth from about 2.5 inches to about 9 inches. 